The present invention relates to a folding chair, and more particularly to a folding chair that enables effectively reduced height and volume of the folding chair in a fully collapsed state.
A fixed chair occupies a specific space even it is not in use. To solve this problem, there are developed various types of folding chairs, so that the chairs may be extended for use or folded to occupy less room for convenient storage.
The collapse volume of a folding chair has influence not only on the convenient storage of the chair by a user, but also on manufacturers"" costs of warehousing and freight, as well as spaces needed by distributors"" for folding chairs in stock.
U.S. Pat. No. 6,213,545 discloses a folding chair that includes a collapsible structure shown in FIG. 1. When the folding chair of U.S. Pat. No. 6,213,545 is in a fully extended state for use, lower ends of its front and rear legs 10, 11 contact at lower ends with a ground surface G and are separated from each other by a predetermined distance. The front leg 10 is connected at upper ends to first pivoting points P1 defined near front ends of two armrests 12; and the rear leg 11 is connected at upper ends to second pivoting points P2 defined near middle points on the armrests 12. A backrest 13 of the folding chair is connected at a predetermined height to third pivoting points P3 defined near rear ends of the armrests 12, and at lower ends to fourth pivoting points P4 defined at upper ends of a pair of knuckle plates 14. A seat 15 of the folding chair is connected at rear ends to fifth pivoting points P5 defined near middle points of the knuckle plates 14, and near front ends to sixth pivoting points P6 defined on the front leg 10. Lower ends of the pair of knuckle plates 14 are connected to seventh pivoting points P7 defined on the rear leg 11 at a predetermined height.
To collapse the above-described folding chair, the armrests 12 and the seat 15 are turned about the third and the fifth pivoting points P3, P5, respectively, to move toward the backrest 13. Meanwhile, the front and the rear leg 10, 11 are brought by the upturned armrests 12 and seat 15 to move toward the backrest 13, too. The folding chair of FIG. 1 in a fully collapsed state is shown in FIG. 2. As can be clearly seen from FIG. 2, although the collapsed folding chair has a largely reduced depth, it has a collapse height H very close to an original overall height of the folding chair in an extended state.
In collapsing the above-described folding chair, the knuckle plates 14 having a predetermined overall length A are turned upside down about the seventh pivoting points P7, causing the fourth and the fifth pivoting points P4, P5 to move downward. A distance C of the rear leg 11 between the second pivoting points P2 and the seventh pivoting points P7 keeps unchanged during the collapse of the folding chair. As a result, the length A of the knuckle plates 14 is restricted to a certain range and could not be too long. Under this condition, a distance by which the backrest 13 could be pulled downward by the turned knuckle plates 14 is small. That is why the collapse height H of the fully collapsed folding chair of FIG. 1 is not effectively reduced.
A primary object of the present invention is to provide a folding chair that enables effective reduction of a collapse height and volume of the chair.
To achieve the above and other objects, the folding chair of the present invention is provided at two armrest members with two long slots forward extended from second pivoting points at joints of the armrest members and upper ends of a rear leg member, so that the second pivoting points are movable when the chair is collapsed. The folding chair of the present invention also includes a pair of knuckle plates that pivotally connect a backrest support member, a seat, and the rear leg member of the folding chair to one another and have length-increased lower portions. Whereby when the knuckle plates are turned upside down during the collapse of the folding chair, the backrest support member pivotally connected to upper ends of the knuckle plates is pulled downward by a longer distance to effectively reduce the collapse height and volume of the folding chair.